Gunsmithing Question - Truing or Blueprinting

[runway1]

Regarding the custom fitting of the action and barrel, sometimes called 'truing' or 'blueprinting', I have a question:

I can see the benefit of aligning everything to the barrel/bolt CL with a controlled feed action, e.g. Mauser, Win 70, etc. Would the benefits be the same or less with a push feed, e.g. Rem 700?

Seems with a push feed action, the whole point is to take away tolerances and mismatch by floating the cartridge into battery without restriction. How would truing the action benefit a push feed? I'm still floating in. All the slop is taken out.

[divingin]

What you are doing with a bolt gun is tweaking everything (barrel-to-action, bolt face to bore line, bolt lugs to action) so that when the cartridge is fired, the recoil doesn't try to skew the case relative to the bore, which would cause the bullet to enter the leade off-center.

Doesn't really have much to do with feeding, as far as I know.

[runway1]

Ahhh. Never really thought of that aspect.

[LynnJr]

99% of your accuracy comes from the barrel and chambering.
The actions role is to keep your brass straight and not to introduce any inaccuracies into the system.
With a sloppy bolt fit the firing pin tries to override the trigger with 18-32 pounds of upward lift. When the trigger is pulled the bolt gets slammed against the abutments sending waves throughout the entire rifle.
Savage deals with this by using a floating bolthead which helps with the unwanted waves but doesn't keep the brass casehead square to the chambering.
That's why Pacific Tool sells oversized bolt bodies. With those oversized bodies you can set the clearance down to a tolerance fit of your own choosing.

[runway1]

Ok. More clear now. Thanks for the explanations!

[jrpowell3]

So how much benefit would I see with an oversized bolt on a stock Remington receiver?

[ar15barrels]

So how much benefit would I see with an oversized bolt on a stock Remington receiver?

As a single factor, that is unquantifiable.

If you have a gun that has a problem with bolt slop and jumps off target, then you would see an improvement about equal to the amount that your gun jumps off target.
I have seen guns that jump off target 3/8 moa or more.
A gun that's shooting 5/8 moa groups while jumping off target by 3/8 moa could theoretically go to shooting 1/4 moa groups once the bolt slop problem is fixed.

[jrpowell3]

As a single factor, that is unquantifiable.

If you have a gun that has a problem with bolt slop and jumps off target, then you would see an improvement about equal to the amount that your gun jumps off target.
I have seen guns that jump off target 3/8 moa or more.
A gun that's shooting 5/8 moa groups while jumping off target by 3/8 moa could theoretically go to shooting 1/4 moa groups once the bolt slop problem is fixed.

You've seen the slop in my bolt, what do you think?

[ar15barrels]

You've seen the slop in my bolt, what do you think?

Does your rifle jump off target while dry firing?

[jrpowell3]

Does your rifle jump off target while dry firing?

I was focusing more on my trigger pull during my dry firing. I'll watch to see if my rifle jumps off target tonight.

[runway1]

That's interesting. Do you dry fire with an empty case and watch the crosshairs? What are you looking for?

[ar15barrels]

That's interesting. Do you dry fire with an empty case and watch the crosshairs?

Yes.

What are you looking for?

Movement of the crosshairs on target.

If the gun is moving on target without a cartridge being fired, you can be assured that it's also moving on target while the bullet is moving down the barrel when you fire a cartridge.
It's hard to hit what you are aiming at if the gun itself is moving away from where you aim.